The use of materials which can be shaped under the influence of heat in medical technology, in particular in orthopedics, is known.
Thus, for example, German Auslegeschrift (German Published Specification) No. 2,758,216 describes a composition which is applied to a flexible carrier material and which can be shaped after immersion in warm water, and solidifies on cooling. This material is preferably used for producing fixed dressings by being applied in the warmed state in the manner of a plaster bandage. However, at room temperature the material is not hard like a high-impact plastic, but has more the consistency of hard rubber. To produce a fixed dressing from this material, it is therefore necessary to wrap round several layers in order to achieve adequate rigidity of the product. For other uses, such as splints, supports and arch supports, the material does not have the required mechanical properties (in particular rigidity), and its lack of transparency is also a disadvantage.
German Auslegeschrift (German Published Specification) No. 2,618,613 proposes the use of rigid foams which can be shaped under the influence of heat to produce fixed dressings in which splints are inserted. The disadvantage of this material is that it requires steam heated to about 120.degree. C. for softening, for which a special apparatus is necessary. These foams are also unsuitable for producing rigid, thin-walled constructions, since not only do they have a rough, porous surface, but they are also still slightly flexible at room temperature.
However, hard, high-impact, transparent materials which can be shaped under the influence of heat can be prepared, for example, by homopolymerization or copolymerization of methacrylates or acrylates and, if appropriate, other monomers containing vinyl units, such as, for example, acrylonitrile. Such materials are chiefly used in orthopedics. The disadvantage of this class of substance is the temperature &gt;140.degree. C. which is necessary to render them flexible. This again requires special apparatuses for warming and shaping.
The present invention was thus based on the object of providing a material which is hard, of high impact strength, dimensionally stable and, where relevant, transparent at room temperature but is flexible and can be shaped and molded at temperatures above about 60.degree. C.